colven



(No Model.) r J. Mi GOLVEN- 2 Sheets-Sheet 1.

SAFETY VALVE.

y No. 404,684.. Patented June 4, 1889.

l wl mda(- ATTORNEYS (No Model.) '2 sheets-sheet 2.

J. M. COLVEN.

SAFETY VALVE.

. Patented June 4, 1889. fag. n

4 l I' j# UNITED STATES PATENT EEICEt JAMES M. COLVEN, OF NEV YORK, N. Y.

SAFETY-VALVE.

SPECIFICATION forming part of Letters Patent No. 404,684, dated J' une 4, 1889.

Application tiled July 31, 1888. Serial No. 281,502. (No model.)

To all wiz/0m t may concern.-

Be it known that I, JAMES M. COLVEN, a citizen of the United States, residing at New York, in the county and State of New York, have invented new and useful Improvements in Safety-Valves, of which the following is a specilication. y

My invention relates to improvements in safety-valves, and has for its object to make the valve more reliable and prompt in its action, and to provide a free escape for the steam while an overpressure exists. The novel features of construction whereby the said object 1s accomplished, together with means-for preventing the valve from being` tamperedwith, are more fully pointed out in the following specification and claims, andl illustrated in the accompanying drawings, in which- Figure l represents a vertical section of a safety-valve embodying my invention. Fig. 2 is a similar view of a modification.

Similar letters indicate corresponding parts.

In the dra-win gs, the letter A designates the valve-shell, which can be attached to a steamboiler or other vessel in which high pressures are carried. In the lower portion of said shell is formed a valve-seat a for the solid valve B, and in the upper portion of the shell' is formed a cylinder A', which is larger in diameter than the valve. In this cylinder is movably iitted a solid piston C, which is rigidly connected with the valve B by the stem b, a convenient way of doing th s being to cast the valve, piston, and stem in one piece. The upward movement of the piston C is limited by a stop d, which may be formed by an open cap or collar d, that` is secured on the top of the cylinder A and overlaps the interior of the same. A suitable steam-inlet e is made in the shell A below the valve B, and a steam-outlet fis formed in the shell, which communicates with the latter between the valve and the piston. A weight D is made to engage with the upper part of the valvestem b to hold the valve to its seat; but I do not confine myself to a weight for pressing the valve to its seat. An overpressure of steam in the boiler slightly lifts the valve B, as usual,whereupon the escaping steam enters the space of the valve-shell A between the valve B and the piston C, and exerts a pressure upon the under side of the piston.

The su perticial area of the piston being in eX- cess of that of the valve, the connected piston and valve are moved upward by the pressure of the steam below and above the valve until the piston engages with the stop d, and they are held in this suspended position, whereby a large area is opened above the valve-seat a for the escape of the steam from the boiler. This action of thesteam can be facilitated by the' use of a cheek against the escape of steam located in the outlet f of the valve-shell. This can consist, as shown in Fig. l, of a valve-disk E, which has al seat g in the outlet f, and is subjected to the action of a comparatively weak spring e', which tends to hold the valve upon its seat. The check shown in Fig. 2 is formed by making the piston C thick enough to normally close and overlap the steam-outlet f, or by providing the same with a circular iiange 7L. When the valve B is lifted up and the escaping steam enters the valve shell between the valve and the piston, it has to move the check before it can escape through the outlet f, so that its action upon the piston is insuredthat is to say, said piston is carried clear up andthe outlet f is thrown wide open.

I'Vhen it is designed to use this safety-valve upon steamboat-boilers, or such boilers as are brought within the exercise of the law regulating the amount of pressure allowed, I incase the valve-shell and its belongings and the weight in a lock-box F, so constructed that the pressure of the weight upon the valvestem cannot be increased without `opening said box.

The box F, in which is secured the shell A, hasopenings in line with the inlet e and outlet f of said shell, and its top is closed by a cover- F which is hinged at c and provided with a lock or seal I-I. Thecover can, however, be secured to the box in any other suitable manner, so that only the proper authorities can gain access to the box. The valvestem b is extended, and in its upper end is formed a recess h, which is engaged by a head t', formed on the lower end of a lifting-rod I, extending through the cover. To the exterior end of this rod I is coupled one arm of a lever J, which is pivoted at j to the cover. When in the position shown in Figs. 1 and 2, the end ofthe lever J rests against a hub on IOO the cover, and the head i' of the lifting-rod is above the` bottom of the recess hin the valvestem. From this it is evident that the lifting-rod cannot be depressed, so as to put an additional weight or pressui'e on the valve B; but it can be raised, so as to decrease such pressure, if desired, and to permit the steam to blow ott.

As seen in Fig. 2, the weight D may be formed of several sections placed together, so that the pressure on the valve B can be adjusted, after which the box is locked.

To preserve a steam-tight tit between the valve B and its sea-t u, I provide the valve with a spiral projection k, which is located on thc under side thereof and causes the same to turn in its up-and-down movement toward and from said seat, Fig. 2. XVhen it is desired to test the boiler, in which case the same is put under a heavier pressure than permitted by the safety-valve, the lock-box is opened and a ring or block placed between the shoulder formed by the collar d and the piston C, which prevents the valve from lifting. This rin g can be placed into the lock-box, as shown in Fig. l.. f

The weight D, instead of being placed above the valve B, as shown in full linesin Figs. l and 2, may be placed beneath said valve, as indicated in dot-ted lines in Fig. l. I must also remark that my valve is so constructed that it forms what may be termed a full-area valve-that is to say, if the diameter of my valve is one inch and it is raised from its seat one-fourth of an inch the area of the opening formed between the seat and the valve is equal te the area of the valve.

\Vhat I claim as new, and desire to secure by Letters Patent, is-

l. The combination of the shell A, having the valve-seat a at its lower end portion, the cylinder A at its upper end portion of a diameter greater than the Valve-seat, and the lateral steam-outlet f, located at a point between the said cylinder and valve-seat, the solid valve B, having a rigid stem b, of less diameter than the valve, the piston C, arranged on the stem and fitting the cylinder, and a weight D, acting on the stem, substantially as described.

2. The conibination, with the shell A, ot the solid valve B, seated in said shell, the cylinder A', formed in the shell. and having a larger diameter than the valve, the solid piston C,fitted into said cylinder and being rigidly attached to the valve-stem d, a weight acting upon the valve-stem, a steam-inlet below the valve B, a steam-outlet which .communicates with the shell A between the valve B and the piston C, and a movable check against the escape of steam through the steamout-let, substantially as shown and described.

3. The co1nbination,with the valve-shell A, having a valve-seat a, a cylinder A,.and a lateral steam-outlet f, located between the cylinder and valve-seat, oit' a solid valve B, the piston C, the lengthwise-movable and axiallyrevoluble valve-stem l), rigidly connecting the valve and piston, and the spiral projection on the valve, substantially as described.

fl. The combination of a valve-shell A, the solid valve B, having the rigid valve-stem and the weight D on the stem, ot' the lock-box F, mounted on the valve-shell, inclosing said shell, stem, and weight, or spring, and a vertical lit'ting-rod I, extending through the top of the lock-box, and on the lower end ot whih rod the Valve-stem is movable lengthwise, substantially as described.

5. The combination of a valve-shell A, the solid valve B therein, having a rigid valvestem provided at its upper end with a recess 7L, the weight D on the stem, the lock-box F, inclosing the shell, spring, and stem, the rigid vertical rod I, projecting through the top ot' the lock-box and having a head i at its inner end loosely engaging the recess of the stem, and the pivoted lever J, engaging the upper en d oli' the rigid rod, substantially as described.

6. The combination, with the valve-shell A, having the steam-inlet e and lateral steamoutlet f, the valve B, the stem Zi, and the weight l.) on the stem, of the lock-box F, carried by the valve-shell, inclosing said shell, weight or spring, and stem, and provided with orifices in line with the steam inlet and outlet of the valve-shell, substantially as described.

In testimony whereof I have hereunto set my hand and seal in the presence of two subscribing witnesses.

JAMES M. TOIJVEN.

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